The XmbDrawString, XwcDrawString
and Xutf8DrawString functions draw the specified text with the foreground
pixel. When the XFontSet has missing charsets, each unavailable character
is drawn with the default string returned by XCreateFontSet. The behavior
for an invalid codepoint is undefined.

The function Xutf8DrawString is
an XFree86 extension introduced in XFree86 4.0.2. Its presence is indicated
by the macro X_HAVE_UTF8_STRING.